Styling options:

Node
-addbeforeskip  make additional request for horizontal space before the node
-addafterskip   make additional request for horizontal space after the node
-disableedgelabelspace set to "yes" to disable additional horizontal
	        space for the edge label of this node
-rightanglededge


NodeLabel
-valign         vertical align of node label, relatively to node oval
-yadj           alter y position of node label
-valign         vertical alignment of the node label    
-dodrawbox      set to "yes" to foce the box even if boxes are not allowed globaly
-nodrawbox      set to "yes" to suppres the box even if boxes are allowed globaly
-xadj

EdgeLabel
-yadj       alter y position of node label (x-coord. is calculated automatically)
-halign     horizontal alignment of the edge label
-valign     vertical alignment of the edge label    
-dodrawbox      set to "yes" to foce the box even if boxes are not allowed globaly
-nodrawbox      set to "yes" to suppres the box even if boxes are allowed globaly
-xadj