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