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