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