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