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