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