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