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)(11,18)(12,20)(13,17)(14,15)(16,23)(19,22)(21,24)(25,26)(27,28)(29,37)(30,31)(32,39)(33,36)(34,38)(35,40)(3,7)(5,8)(10,15)(11,17)(16,20)(19,21)(25,27,30,33)(26,28,31,36)(29,34,39,40)(32,35,37,38)(1,2)(3,5)(4,6)(7,8)(10,15)(13,18)(16,20)(22,24)(26,31)(27,33)(32,37)(34,40) involution — undirected(1,3)(2,5)(4,7)(6,8)(9,11,14,17)(10,13,15,18)(12,21,23,19)(16,24,20,22)(25,28)(26,27)(29,38)(30,36)(31,33)(32,40)(34,37)(35,39)(1,2)(3,5)(4,6)(7,8)(9,12,14,23)(10,16,15,20)(11,19,17,21)(13,22,18,24)(25,29)(26,32)(27,34)(28,35)(30,39)(31,37)(33,40)(36,38)(9,13)(10,17)(11,15)(12,22)(14,18)(16,21)(19,20)(23,24)(25,26)(27,28)(29,32)(30,31)(33,36)(34,35)(37,39)(38,40) involution — undirectedA 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.