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