Many ferrets love to dig.  They'll dig in their litter pans, under the
cushions of the couch, and at the carpet near closed doors.

To get your ferret to stop tossing litter all over, start out by
putting less in the pan, and keep it just clean enough that there's a
dry layer on top.  Litter digging tends to be a kit behavior, perhaps
because kits have so much energy and are often cooped up in cages, so
with time and luck your ferret will grow out of it.

It's nearly impossible to train a ferret not to dig at all, so you're
better off protecting your property [5.2] and removing the temptation.
Some digging, especially in the litter pan, can be out of boredom, so
playing with the ferret more can help, too.  You can also help control
your ferret's digging by giving her somewhere approved to dig.  A box
filled with dirt, sand and gravel, then set into a larger box to
contain the mess, can be great fun to a ferret.  Your ferret may also
enjoy digging outside, closely supervised of course.