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