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