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