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