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