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