Yuna- In my opinion I would say make the dress colors the same as they show up in the movie as one color. It's hard to see the different colors from the movie version because they are so splattered together. Use the first link as a guide for the splatters as I think this looks like the best interpretation of it. If you aren't sure what the colors for the two dresses are I can help you out with that. The blue version has light periwinkle sleeves and peplum with a royal blue bodice and a shade or two lighter than royal blue for the skirt. The pink dress has light pink sleeves and peplum with a dusty rose pink bodice and the skirt is somewhere in between the color of the sleeves and bodice, about a medium pink. It's basicaly the concept of taking both dress colors and throwing them together. I hope this helps.
Sleeping Beauty is my fav movie and although I am partial to the blue version I do love seeing the variations people come up with.