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