Plasti-dip for changing cable colors?

No problem. What I meant was that when you route or rearrange cables, they rub against the case and each other. The plasti-dip is glossy but scuffs easily, so after you coat cables and try and run them they will probably get scuffed. Not only that, but plasti-dip that is not black can be a stain absorber. Not a problem after it is in the case, but it can get discolored by a brush with an orange. One dropped from a table for my friend as his plasti-dip was setting and left a noticeable light orange tint to a spot on his white wheel. Not fun...

The simple solution is to use something that is flexible and sturdy and computer hobbiests in the past used bicycle handlebar tape. It is available in many colors and you can get it in foam rubber / nylon / latex so that it will suite whatever type of cable routing and appearance you need. Just don't wrap the cable too tightly, and you will be able to route it through the case and the tape can take a fair amount of stress.

When people use plasti-dip it is pretty typical to have to try 2 or 3 times to get everything right. Each attempt creates fumes and uses more of the plasti-dip. With handlebar tape you might loose an inch or two of tape when you redo an area, but there are no fumes and it is meant to stay in contact with people who have oily skin and sweat - so it usually stands up well.

No, it does not have an adhesive compound. It sticks to itself, because of the materials that it is made of.

It is true that you can get either type - I ride bicycles as a hobby and some places carry the regular tape kind, but a bicycle shop will normally only carry the self (or non) adhesive type. If you get them online, the ones that you want will normally be called non-adhesive.

Think of it as being tacky - the tape will not slide easily on a flat surface and it will grab itself. It takes a little practice to put it on, but you can try several times with the same piece of tape. For the starting end you can cut or fold the edge (usually to a 30 or 45 degree offset) - for computer cables you can tuck the edge under part of the cable. The end part will always need something to keep it in place; on bicycles that is the handlebar trim plug. For computers you need something else.

I normally used to use a piece of black "heat shrink tape" on each end to make sure it never came undone. The starting area holds up initially, but it will slip over time. By melting a small piece of heat shrink tape to each end, you keep everything in place. It can be tricky to heat up the heat shrink tape without damaging the bicycle tape. The heat shrink tape should be wrapped loosely in two layers on the end and heated to the point that shrinks to grab the bicycle tape underneath it. A heat gun is the best thing to use, but I normally used the large heat venting area of a soldering iron (just below the handle, but before the tip area).

The heat shrink tape is very solid, but would take way too much time to apply to an entire cable. Plus it does not shrink in a way that works well if you try and spiral wrap it to cover a cable. This part is usually something you will want to practice on a junk set of cables with until you get comfortable with it. I picked it up pretty well after 2 or 3 days of practicing in my spare time (about 2 hours of total practice).

A roll of one inch black heat shrink tape costs about $6 to $15 depending on where you get it. One roll will last you forever, or until you lose what is left of it