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