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