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