On my special machines I make my design plans using solidworks for the 3D of the cable with connector, then in the drawing j insert the wiring/welding drawings of the cable color sockets using draftsight in 2D.
edit: the more precise the 3D of the connectors the easier it is for the representation
Have you looked at SolidWorks Electrical, maybe that's what you need.
I guess you make harnesses to connect your various electrical components of your machines, and from the little I've seen on SolidWorks Electrical, it knows how to handle that.
@Coyote: I know SolidWorks Electrical, we are presented with great demonstrations at the kickoff. But given the price of a SolidWorks Electrical license and not to mention the necessary training, it's not even an option.