One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,7)(3,8,4,6)(9,10,16,20,14,19,15,22)(11,21,17,27,24,12,25,33)(13,28,34,37,31,18,32,36)(23,26,38,40,29,30,35,39)(1,3,5,4)(2,6,7,8)(9,11,14,24)(10,12)(13,29,31,23)(15,17,16,25)(18,30)(19,21)(20,27)(22,33)(26,28)(32,35,34,38)(36,40)(37,39)(1,4,5,3)(2,6,7,8)(9,12,14,21)(10,17,19,25)(11,22,24,20)(13,30,31,26)(15,33,16,27)(18,35,28,38)(23,36,29,37)(32,39,34,40)(3,4)(6,8)(9,13,14,31)(10,18,19,28)(11,23,24,29)(12,26,21,30)(15,34,16,32)(17,35,25,38)(20,37,22,36)(27,40,33,39)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.