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