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