Here:
Pelican Parts - Porsche 914 Electrical Diagrams
The two relevant diagrams are:
http://www.pelicanparts.com/914/parts/electrical/914_electric_71A.jpg
http://www.pelicanparts.com/914/parts/electrical/914_electric_71b.jpg
The same diagrams (in B&W) are also found in your Haynes manual. (If you don't have one, get one.)
The layout of the wires is close to where they actually are on the physical gauges. The terminal numbers match exactly, though. So use those--they should be next to the terminals on the gauges.
If you have questions, you can ask here.
Wiring colors, unless someone has hacked with them, are pretty consistent. Solid black or solid red are power; black/blue (black with a blue stripe) is instrument illumination power, brown is ground, and so on.
--DD