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