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