Hi Shaun88 , you will find that there is a variety of colors to give people options when choosing their ram with a particular color scheme in mind,
basically you can get a 1600mhz kit the same speed and latency in multiple colors to suit the look of your board or 1866 or 2133 and so on.
so if you have a motherboard with black and blue colors you might go with the blue colored ram or a red and black motherboard you might go with the red colored ram etc etc