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