The symmetrical layout represents an implementation of the Fruchertman and Reingold force directed layout (with some modifications).

It uses attractive and repulsive forces, which aim to produce a drawing with uniform distance between each set of connected vertices. Because of that the drawing tends to be symmetrical.

The attractive and repulsive forces are coupled in an instance of the NDesiredDistanceForce class, accessible from the DesiredDistanceForce property.