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