private void button2_Click(object sender, System.EventArgs e) {

string strCmdLine1 = "-Tsvg -o c:\\tmp\\foo.xml c:\\tmp\\ER.dot";
string strCmdLine2 = "-Tsvg -o c:\\tmp\\foo.xml c:\\tmp\\Heawood.dot";
System.Diagnostics.Process p = new System.Diagnostics.Process();

p.StartInfo.FileName = "\"C:\\Program Files\\ATT\\Graphviz\\bin\\dot.exe\"";
p.StartInfo.CreateNoWindow = true;
p.StartInfo.UseShellExecute = false;
if (graphIndex == 0)
p.StartInfo.Arguments = strCmdLine2;
else
p.StartInfo.Arguments = strCmdLine1;

p.Start();
p.WaitForExit();

axSVGCtl1.reload();
graphIndex = (graphIndex + 1) % 2;
}

http://vv.cs.byu.edu/cs312-003/archives/2005/01/graph_visualiza.html

Graph Visualization and Layout in C# using AT&T's Graphiz and an SVG viewer

C#