Yummy. Nothing puts Mr. Rewrite in the mood to buy groceries more than seeing the term "Floor Diaper" at his supermarket. Come to think of it, Mr. Rewrite could have used a few floor diapers when Rewrite Jr. was transitioning away from Huggies. But that isn't the point of this post.
If you are bound by the AP Stylebook, which almost certainly isn't the case with this store, here's what it says about cleanup/clean-up/clean up:
It's cleanup as a noun. For example: "Bring the floor diaper for a cleanup in the produce aisle."
It's cleanup as an adjective. For example: "The cleanup crew took care of that produce aisle disaster by swiftly deploying a floor diaper."
It's clean up as a verb. For example: "Get the @#$%*&@ floor diaper and clean up that disaster in the produce aisle."
Because cleanup is the adjective, there's no case in which you'd need to hyphenate the term.
Let's all review our AP Stylebooks and clean up our writing. If not, Mr. Rewrite will hit your prose with the editing equivalent of a floor diaper.