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