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