PEX Tubing for PEX Plumbing comes in red, white, and blue colors. All three colors are made of the same material, and will function exactly the same. The colors are only there to make looking at your pipes and knowing which pipe goes where easy. Red is typically used for hot water and blue is typically used for cold water. If you don't want the colors, you can use white everywhere.
PEX Tubing can be found at www.supplyhouse.com