Create a Graph-like Content Type with Nodes and Links

Basically, I need an administrator to create a graph (like react-digraph: GitHub - uber/react-digraph: A library for creating directed graph editors)

Does that clarify things? I tried a few approaches and I can’t find one that works.

While I can achieve something like this through just free-text inputs. Ideally, I’d like a way for the admin to be able to select the nodes and not just type it through free text.