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