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