@Bank_Live, I don’t think there is currently any real integration with draw.io diagrams as in the example you gave.
The Graphviz plugin mentioned may work all right for small diagrams that are simple enough to express in text form. But a lot of the Diagrams/Draw.io items are much more complex.
There was some discussion about an approach many years ago over at:
and then a related discussion about using a similar tool, Gliffy:
At one point (in that above topic) @mpalmer was interested in building a linkage to Draw.io but I don’t think anything became of it. I got a request today about this so will be doing some more research on what’s possible. It may be possible to embed an IFRAME from the Draw.io interface and use that HTML that it generates in your Discourse post.