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