I've begun work on modifying the myOmxGraphviz functions so that it picks up on the values and places them onto relevant paths (with some other todo and suggestion stuff in there also. For instance, if variables have paths coming in and out already, residual paths should move out of there way. If a manifest has an outgoing path, the residual should try and get onto the north side. one-arrow lines should be straight (not sure if graphviz knows about that).
anyhow, the working functions are here
if you paste them into R you can use
myOmxGraphviz(fit , "test.dot"); system("open test.dot")
to call the new functionality, and see how it looks (assuming you have graphviz installed)