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