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