Books dedicated to graph layout:

Di Battista, Giuseppe, Peter Eades, Roberto Tammassia, and Ioannis G. Tollis. Graph Drawing: Algorithms for the Visualization of Graphs, Prentice Hall, 1999. See:

or

http://www.mypearsonstore.com/bookstore/product.asp?isbn=0133016153.

Kaufmann, Wagner (Eds.): Drawing Graphs, Lecture Notes in Computer Science Vol. 2025, Springer 2001. See:

http://link.springer.de/link/service/series/0558/tocs/t2025.htm.

Graph layout is closely related to graph theory. See:

Clark, John and Derek Allan Holton. A First Look at Graph Theory. World Scientific Publishing Company, 1991.

For a mathematics-oriented introduction to graph theory, see:

Diestel, Reinhard, Graph Theory, 2nd ed., Springer-Verlag, 2000.

A more algorithmic approach is found in:

Gibbons, Alan. Algorithmic Graph Theory. Cambridge University Press, 1985.

Gondran, Michel and Michel Minoux. Graphes et algorithmes, 3rd ed., Eyrolles, Paris, 1995 (in French).