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