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