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