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