I wish I could see how much root (rhizome) was left where all the leaves connect? Keep in a moist area but don't water in the soil. Roots will re-grow if given enough time. You don't want the sun to dry it out so keep it in the shade. I use a mister to keep the leaves from drying out and no water in the soil. Also the soil is important. I hope it is a cactus mix with fast draining.
You can start to water only after you see some growth. Also if there is not enough rhizome left. It may loose the yellow edge in the new growth.
These are really tough plants. It should rebound in a few weeks or so.

It's hard to say what's wrong w/ it since the pic doesn't show the bottom of the plant. I really wouldn't know what to suggest other than turning it out of the pot to see what's going on in the roots. It's the only way to know for sure.

That's the only way to diagnose this, sorry, I wouldn't care to guess at remedies otherwise.