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