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