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