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