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