So you see each face colored black all on a white background.
Not exactly, it shows white faces defined with black lines on a white background. Assuming you want the lines colored green and the background a color other than white you can try the following:
Add a levels adjustment layer to make all the lines dark (some are gray) and make the background white.
Add a solid color adjustment layer (green) whose blend mode is set to Screen
Add a solid color adjustment layer (yellow) whose blennd mode is set to Linear burn
Numerous variation on this approach can used - assuming this is what you want
Hi Paulo, looking at your picture in response, this is exactly what I need to do, (except different colors). I'm sorry, but I am definitely a newbie using photoshop. Would you be able to explain it more in depth? That would be so great. Because I've attempted to do what you said, but was having serious trouble.
An open ended request for more detail does not usually work out well. If you can be specific about what step you are having difficulty with I, or others, can probably reply.
I would point out that to simplify matters a little you can initially eliminate the step using the Levels adjustment layer. Depending on your needs that step may be unnecessary. So what you need to know is how to add a solid color adjustment layer and how to set a blend mode.
Did you try D Fosse's idea? It's even more direct than Paulo's, though Paulo's yields more adjustable results.
You will not be able to learn Photoshop by asking questions alone - you'll have to use it to get to know it. The things being described above are pretty basic (e.g., choose Image - Adjust - Levels, or Layer - New Fill Layer). Learn to use the Help facility in Photoshop to find out how to do something someone has described to you.