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