It would be very helpful for students if posters like these were posted either on the walls by the classroom library, or used in the library at each genre. Students would subtly learn what each genre consists of if they see these images everyday, and could eventually figure out what genre they enjoy reading most.
We've created some simple genre posters to display in your classroom. Each one has the definition of the genre and some examples. This is a good visual way to remind your students to vary their reading during workshop. You can refer to them in conferences and even have your students sort their books according to them!