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