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