TBH I think the Argdown source is much more readable than this I found from one of your links:
/* Example */
digraph {
/* Note: HTML labels do not work in IE, which lacks support for <foreignObject> tags. */
node [rx=5 ry=5 labelStyle="font: 300 14px 'Helvetica Neue', Helvetica"]
edge [labelStyle="font: 300 14px 'Helvetica Neue', Helvetica"]
A [labelType="html"
label="A <span style='font- size:32px'>Big</span> <span style='color:red;'>HTML</span> Source!"];
C;
E [label="Bold Red Sink" style="fill: #f77; font- weight: bold"];
A -> B -> C;
B -> D [label="A blue label" labelStyle="fill: #55f; font-weight: bold;"];
D -> E [label="A thick red edge" style="stroke: #f77; stroke-width: 2px;" arrowheadStyle="fill: #f77"];
C -> E;
A -> D [labelType="html" label="A multi-rank <span style='color:blue;'>HTML</span> edge!"];
}