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