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