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