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