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