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