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