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