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