I have already found the "Request Preview" page, apart from that is there any way to deploy and test Neptune locally?
AWS Neptune can be tested only from within the VPC. What you can probably do is
1. Create an ec2 instance in the same VPC
2. Install Gremlin/ SPARQL console in ec2 (if you need to execute queries)
3. connect to Neptune via ec2
4. Execute queries
Neptune DB can be either SPARQL/ Gremlin. It is based on the first query you hit.
If SPARQL, metaphacts can be used for the visual representation of the database.