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