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