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)(16,20)(17,21)(18,24)(22,23)(25,26)(27,36)(28,31)(29,34)(30,33)(32,35)(37,40)(38,39) involution — undirected(1,3,6,7)(2,4,5,8)(11,17)(15,21)(18,23)(22,24)(25,27,32,30)(26,33,35,36)(28,37,29,38)(31,39,34,40)(1,2,6,5)(3,8,7,4)(10,14)(15,21)(16,19)(22,24)(25,28,32,29)(26,31,35,34)(27,37,30,38)(33,39,36,40)(1,4)(2,7)(3,5)(6,8)(9,10)(11,15)(12,16)(13,14)(17,21)(18,22)(19,20)(23,24)(25,29,32,28)(26,34,35,31)(27,38,30,37)(33,40,36,39)(1,4)(2,3)(5,7)(6,8)(9,11)(10,15)(12,18)(13,17)(14,21)(16,22)(19,24)(20,23)(25,30,32,27)(26,33,35,36)(28,38,29,37)(31,39,34,40)(1,5,6,2)(3,8,7,4)(9,12,13,20)(10,16,14,19)(11,18,17,23)(15,22,21,24)(25,31,32,34)(26,28,35,29)(27,39,30,40)(33,37,36,38)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.