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