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