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