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