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