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