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