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