Well, kind of.
At Savi's, your color options will be blue, green, red or purple.
You can purchase additional kyber crystals at Dok-Ondar's Den that include white and yellow, and will turn your blade that color.
Or, you can buy a RFID chip reader/writer and change the RFID code on any color crystal to turn your lightsaber any of the above colors. I've never done this, but there is a bunch of information online about how to do it, and it looks pretty straight forward.