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