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