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