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