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