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)(11,18,19,14)(13,15,21,17)(20,22,24,23)(25,26)(27,30)(28,32)(29,31)(33,37)(34,39)(35,38)(36,40)(2,5)(6,7)(9,11)(10,14)(12,19)(13,20)(15,23)(16,18)(17,22)(21,24)(25,27,28,34,29,35,36,33)(26,30,32,39,31,38,40,37)(10,15)(11,19)(13,21)(14,22)(16,17)(18,23)(27,33)(28,36)(30,37)(32,40)(34,35)(38,39) involution — undirected(1,3,4,8)(2,6,5,7)(10,16)(11,19)(15,17)(20,24)(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.