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