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