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