Mark Watson's book (free pdf version: http://www.markwatson.com/opencontent/book_java.pdf), a lesser known Clojure book he self-published last year, covers some useful graph technology, mainly allegrograph.
I myself don't have much experience with graph db libraries, but the above-cited book mentions that neo4j is optimized to traverse graphs, whereas allegrograph is optimized for subgraph matching. So the choice will likely depend on your specific application.
If you go with allegograph, the author of that book waives the AGPL license on his wrappers for production use if you buy copies of his book, and of course can be used under the conditions of the license freely https://github.com/mark-watson/java_practical_semantic_web
The clojure-neo4j wrapper library exists, though it's unclear if it would be code-rotted or ready for use given the last commit date https://github.com/JulianMorrison/neo4j-clojure. The most recently updated fork, by mattrepl, however was not that long ago: https://github.com/mattrepl/clojure-neo4j.git