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