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