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