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