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