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