See this guy doing it with the whole dough, it is an amazing site:
The original color is white-ish, the color of the flour dough. But the local Chinese lady probably adds yellow food color to make them look the way they look in this picture.
One good way to prepare a noodle meal is to fry some well-marinated chicken with black pepper and canola oil, fry cut bits of carrots, lettuce and green pepper and mix everything with the noodles in a pan and cook/fry for a few minutes while mixing the ingredients with the noodles.
Quickly prepared and taste delicious!