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