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)(27,35)(28,32)(29,33)(30,40)(31,34)(36,37)(38,39)(1,2)(3,6)(4,5)(7,8)(10,12)(15,17)(16,20)(22,23)(25,26)(27,35)(28,32)(29,30)(31,34)(33,40)(36,39)(37,38) involution — undirected(2,5)(3,7)(10,12)(13,21)(15,17)(18,24)(25,27,31,28)(26,32,34,35)(29,38,40,36)(30,39,33,37)(3,7)(6,8)(9,11,14,19)(10,15,12,17)(13,18,21,24)(16,22,20,23)(25,28,31,27)(26,32,34,35)(29,36,40,38)(30,39,33,37)(1,3)(2,6)(4,7)(5,8)(9,12,14,10)(11,15,19,17)(13,20,21,16)(18,22,24,23)(25,29)(26,33)(27,36)(28,38)(30,34)(31,40)(32,39)(35,37)(1,2)(3,6)(4,5)(7,8)(9,13)(10,16)(11,18)(12,20)(14,21)(15,22)(17,23)(19,24)(25,30,31,33)(26,29,34,40)(27,37,28,39)(32,36,35,38)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.