A local alternative to Al's wire marking tape are
these books of wire marking stickers. $7.96 at Home Depot.
Like 111, we don't bother with a schematic. Instead, we print the robot map from the robot program and use that as a reference. That, plus wires marked at both ends (yes, every wire), is adequate.
One other tip. Always connect motors and power to speed controllers with the red wire connected to the positive terminal and the black wire connected to the negative terminal. If you notice that your motor is turning backwards, it's tempting to fix it by swapping the polarity of the wires. The problem is that you need to remember that orientation if you replace a part. Better to do the swap in the program and have the physical wiring on the robot standardized.