Online source to buy magnificas, Liveaquaria and bloozoo have them in sometimes. To get colorful ones, good luck, you and the rest of the nem heads on reef central including my self are always looking for colorful ones like vultures.
A simple google search of magnifica sea anemone results in hundreds of pictures of different color variations, more than I could post in any reasonable time on here.
The normal color you will see is tan base, tan/brown tentacles, white tips.
Harder to find, purple base, and or green/yellow tipped tentacles
Hard to find still, red base, and or purple tentacles, pink or green/yellow tips
Hope that helps.