On the external ports, they are the two blue USB ports below or next to (depending on how you are looking at the board) the two P/S2 mouse and keyboard ports. There are no USB3.0 ports on the board internally.
then what should I do about the cable that is connected to front panel?
You can get a internal usb 2.0 to usb 3.0 connector cable. The front face will only run as a 2.0 but it will at least run. I do not know if you can buy thease cables but my Asus Sabertooth Z87 motherboard came with one.
If you have holes in the rear of the case for water cooling, get a cable that will plug into the back and run it into the case for the front panel cable.