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