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