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