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