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