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