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