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