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