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