"Graphic" books are cataloged in Dewey with the number 741.5 which is the number for comic art. But Mr. Dewey didn't anticipate that SO many wonderful fiction books would be written in graphic form, so most librarians pull their 741.5 section and put it near the fiction books.
We did that too, but now we've gone a step further and changed the 741.5 label to GRA (for "graphic"). Next we sorted our graphic books by type. We've added a line to each label to show what type of graphic book it is.
Here's our system:
F (for longer stories/novels)
Author's name OR Original Author's name (keeps adaptations together, like Shakespeare, Riorden)
COM (for comics)
Character's name (Batman, Spiderman, etc)
MAN (for Manga)
### (Dewey number - for nonfiction)
Hooray for catalog tweaks! Next...I have my eye on the 800s... Stay tuned!