Our website provides a free download of Graphviz 2.4 for Mac. The software relates to Design & Photo Tools. The actual developer of this free Mac application is Pixelglow Software.
From the developer:
Graphviz is Open Source graph-visualization software.
You may want to check out more Mac applications, such as XDot, Synalyze It! Pro or Trout Mind Mapping, which might be similar to Graphviz.