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