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