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