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)(20,23)(21,22)(26,30)(31,36)(32,37)(38,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,11)(10,15)(12,20)(13,17)(14,19)(16,24)(18,22)(21,23)(28,35)(32,37)(33,39)(38,40) involution — undirected(2,5)(6,8)(10,13)(15,17)(16,21)(23,24)(25,26)(27,31)(28,32)(29,30)(33,38)(34,36)(35,37)(39,40) involution — undirected(3,7)(6,8)(9,11)(10,15)(12,20)(13,17)(14,19)(16,24)(18,22)(21,23)(25,27,29,34)(26,31,30,36)(28,33,35,39)(32,38,37,40)(1,3)(2,6)(4,7)(5,8)(9,12,14,22)(10,16,13,21)(11,18,19,20)(15,23,17,24)(25,28)(26,32)(27,33)(29,35)(30,37)(31,38)(34,39)(36,40)(1,2)(3,6)(4,5)(7,8)(9,13,14,10)(11,17,19,15)(12,21,22,16)(18,24,20,23)(25,26)(27,31)(28,32)(29,30)(33,38)(34,36)(35,37)(39,40)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.