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