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