There aren't many great flow and diagram libraries out there, and even fewer focus on React.
I suggest looking into a generic solution that integrates well with React.
If this is in a commercial context and/or your requirements are non-trivial, be sure to check out yFiles for HTML, which is the most powerful library available when it comes to sophisticated diagramming. It also comes with a React Diagram Integration Demo. This allows you to use all the features in a React powered application.
Disclaimer: I work for the company that creates the mentioned library. I do not represent my employer on SO, though. This is my very own opinion.