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