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