I've been pursuing a better way of drawing maps (vector images) for some time.
As of May 2017, draw.io moved to an Apache 2.0 license. In August 2017, they released desktop versions to complement the browser-based versions that were previously free. See my digest of these events at "Draw.io open source".
There's a repository for jgraph/drawio on Github.
For Dokuwiki, I notice a draw.io Pluign for DokuWiki on Github, and a 2017-2018 forum discussion. I haven't fully investigated these yet.
Instead of trying to replicate the rich functionality in draw.io, what would an integration with federated wiki look like?