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