One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(3,4)(7,8)(9,10,14,20,15,18,13,19)(11,21,23,33,25,16,24,32)(12,26,29,17,30,36,28,35)(22,34,38,31,39,40,27,37)(1,2,5,8)(3,7,4,6)(9,11,15,25)(10,16,18,21)(12,27,30,38)(13,23,14,24)(17,34,35,40)(19,32,20,33)(22,29,39,28)(26,31,36,37)(2,6)(3,4)(7,8)(9,12,15,30)(10,17,18,35)(11,22,25,39)(13,29,14,28)(16,31,21,37)(19,36,20,26)(23,27,24,38)(32,34,33,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.