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