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