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