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