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