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