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