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