The brown color comes mainly from soy sauce that is added for flavor and the color.
I Start by adding the rice to the wok then tossing in the cut up meat (since this is a "leftover"dish meat is already cooked, if you are using raw cook meat first then add rice.) Whisk a few eggs in a bowl, clear a spot in the center of the rice, pour egg into center so it hits the hot pan, stir to get egg done and mix in with the rest of the dish. Add your veggies, green onion, peas..what ever. Add soy sauce to taste. It will take quite a bit since the rice is very bland you can add quite a bit.
If you want a healthier version and one that will turn out a bit darker start with brown rice.
Remember the rice is better if it is made the day before. It has to go into the wok cold.