I would ask, but if you really want it to be a surprise, try to find out what colors she likes or decorates with and make something geometric and modern-ish in either solids or non-busy prints. Unless you know she likes traditional quilt designs, florals, or batiks I wouldn’t use them. Something like this is probably more likely to appeal to them:
https://www.vacilandoquilting.co/sho...n-tutorial-pdf