dot - makes ``hierarchical'' or layered drawings of directed graphs. The layout algorithm aims edges in the same direction (top to bottom, or left to right) and then attempts to avoid edge crossings and reduce edge length.
neato and fdp - make ``spring model'' layouts. neato uses the Kamada-Kawai algorithm, which is equivalent to statistical multi-dimensional scaling. fdp implements the Fruchterman-Reingold heuristic including a multigrid solver that handles larger graphs and clustered undirected graphs.
dot - makes ``hierarchical'' or layered drawings of directed graphs. The layout algorithm aims edges in the same direction (top to bottom, or left to right) and then attempts to avoid edge crossings and reduce edge length.
neato and fdp - make ``spring model'' layouts. neato uses the Kamada-Kawai algorithm, which is equivalent to statistical multi-dimensional scaling. fdp implements the Fruchterman-Reingold heuristic including a multigrid solver that handles larger graphs and clustered undirected graphs.
source: http://www.graphviz.org/