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