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