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