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