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