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