Hi,
I had the same problem with my little ones. Even though crayons are non-toxic, I was always worried about the possibility of choking on chunks of them... as well as the dubious nature of having a diet largely comprised of wax.
We switched to washable crayons (Crayola) which are non-toxic and kind of melt when they get wet. The kids could color, the baby could munch at will and I could safely navigate the crayon-eating stage while I slowly taught her that crayons were "not for the mouth."
I limited the time, space and outfits allowed for coloring. It was my way of limiting the mess and controlling how much my kids ingested (because let's face it, even non-toxic melty washable crayons aren't exactly the most nutritious thing). Making a mess is 98% of the fun, so I just set things up accordingly and let them have an hour of wildly uncivilized behavior.
Also, be aware that if you use washable crayons, you will have a child entirely painted with melted color -- and it will dribble as they drool. I simply let my kids color in their swim suits, naked, diaper only, or in 'art outfits' that we had for cold weather days. Always put a tablecloth down on the floor (or patio) under where they are doing their coloring (this is a good idea for clay, as well) because the chewed up bits of crayon frequently get tracked all over. A tablecloth is easy to just bundle up and shake out over the lawn before tossing it in the washer.
As for breaking her of the phase: just use consistency and patience. It will pass, but it takes a bit of time. The washables take the stress out of it -- and they make for some great keepsake photos. 'Cause who doesn't love a picture of a half-naked purple and green baby?
Best of luck! :-)