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