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