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