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