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