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)(27,33)(28,36)(29,34)(30,31)(32,35)(37,39)(38,40)(2,5)(6,8)(9,11,14,21)(10,15,18,24)(12,20,13,19)(16,23,17,22)(25,27,29,30)(26,31,34,33)(28,35,38,37)(32,36,39,40)(9,12,14,13)(10,16,18,17)(11,19,21,20)(15,22,24,23)(25,28,29,38)(26,32,34,39)(27,35,30,37)(31,36,33,40)(9,13,14,12)(10,17,18,16)(11,20,21,19)(15,23,24,22)(25,26)(27,31)(28,32)(29,34)(30,33)(35,36)(37,40)(38,39)(1,3,4,7)(2,6,5,8)(10,18)(15,24)(16,17)(22,23)(25,27,29,30)(26,33,34,31)(28,37,38,35)(32,36,39,40)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.