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