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