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