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