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