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