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