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