Does she look gravid? It's usually pretty clear when they have a belly full of eggs. If so you may want to cover the cage and give her some privacy to let her dig. I've only bred panthers but when they lay it sometimes takes a few days once they start going to the bottom, often they dig a few false or test holes before actually laying. I have even had a few lay overnight. When they go off feed in conjunction with other signs is usually a good indication they will lay very soon. Be sure to have plenty of healthy high calcium feeders for after she lays and give extra hydration to help her recover quickly.