User blog comment:CureHibiki/Mahou Tsukai Pretty Cure speculations!/@comment-9442368-20151128042424

My guess is because the broom-like thing in the logo resembles a paintbrush as well. It looks like it's painting that rainbow.

Makes me wonder if they'll go with pink/purple/yellow/blue because the last two colors are present in also every series, but I hope there's a green Cure in there somewhere. I think it would be cool if there were to be siblings in the group this time around.