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