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