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