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