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