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