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