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