I did use Graphviz tool (http://www.graphviz.org/) for more than ten years now -- really cool.
In my 2nd WSTE DataPower webcast back in 2010 you can see on slides 16-18 on how I did use Graphviz for DataPower:
On slide 10 of 1st 2010 WSTE webcast you can see that we use Graphviz in DataPower Compier development as well (top right):
Until now I never worked further on providing solutions for DataPower involving Graphviz externally of IBM.
Reason was that I deemed setting up a Web server based Graphviz solution as difficult.
Just now I notized the amazing work on Viz.js:
I did try to get Viz.js running by downloading and running make.
Problem was that emscrypten was not installed, and while there are easy solutions for Windows and Mac OS and some flavors of Linux, for my Redhat flavor of Linux things were not that easy.
BUT the Viz.js example.html page is online, you can just try it out !
AND even better, you can just save the sample page from your web browser as "Web Page, complete", and it will store the HTML page as well as viz.jz allowing you to work with it locally (even without network connectivity).
I just copied the saved sample and reduced it to the bare minimum -- WOW!