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