Well, you're right, usually they don't move around when they're in blue, but since you just got her I'd say it's because she's still settling in. Most snakes are usually a little freaked out when they get moved from place to place, and feel like they have to explore. I'm sure she will calm down and hide in the next couple of days, probably even tomorrow. Leaving her alone to relax (and raising the humidity of course - I'm sure she will be fine with you opening the tub to spray) are the most important things