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