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