[Mechvet]

Look into using Solidworks Electric tied into the Solidworks routing plugin.

In short, here's what you end up with:
1. A harness diagram for making the entire robot's harness OFF the robot.
2. Ensuring that everything fits, and all spaces clear the # of wires required.
3. Wires can be accounted for in weight during your robot design.
4. Good experience in proper electromechanical design.

There's tons of youtube tutorials out there that will teach you everything you need to know about SW electrical.