JsonDocs is a NPM module that generates minimalistic documentation for a given JSON schema. You can view an example here
JsonDocs is a command line app that when passed a JSON schema file called example.json will output a new file called example.json.html
sudo npm install -g jsondocs
Then simply
jsondocs schema.json
You should now have some raw HTML which can be themed.
Use this themed example output as a basis.
This is made for draft v4 and highly untested. If you like the concept please leave new issues and we can go from there.