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