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