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