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)(11,18)(12,16)(13,22)(14,19)(15,20)(17,21)(23,24)(25,26,30,28)(27,31,34,36)(29,37,39,32)(33,35,40,38)(2,5)(6,8)(9,11,12,19)(10,14,16,18)(13,20,21,23)(15,22,24,17)(25,27)(26,31)(28,36)(29,38)(30,34)(32,40)(33,37)(35,39)(3,7)(6,8)(9,11)(10,15)(12,19)(13,23)(14,17)(16,24)(18,22)(20,21)(25,28,30,26)(27,33,34,40)(29,32,39,37)(31,38,36,35)(1,3,4,7)(2,6,5,8)(11,19)(14,18)(15,24)(20,23)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.