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