I would say, just design how you see it in your mind.
After all that’s the whole point of Dgraph.
You mimick graph structure as you see them in your mind, and alter the schema as you go. Unlike SQL or NoSQL, you are not tied down to ghosts of your past.
Checkout: Loading close to 1M edges/sec into Dgraph & Did I hit 1B+ transactions w/ Dgraph? for proof that it can handle anything you throw at it.