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