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