Vince - "a set of MagicMarkers and the B&W one blown up to poster size??"
That's probably the only way you're going to get a colorized version - I don't know of anyone who does a color version of the TD wiring diagrams (someone, years ago offered diagrams printed on silk fabric, but not in color). The TD wiring diagrams are not all that hard to follow (there ain't that many wires in the whole car) and each line is marked with a number that corresponds to the wire color (referring back to the color code on the first page). Just take the page into Kinko's and have them make a 2X copy of it and laminate it - you can then trace the lines you are concerned about with a grease pencil.
Cheers,