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