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