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)(11,14)(12,15)(13,16)(17,21)(18,22)(19,23)(20,24)(25,26,32,35)(27,30,34,31)(28,38,37,36)(29,33,40,39)(1,3,5,4)(2,6,7,8)(9,11)(10,14)(12,19)(13,17)(15,23)(16,21)(18,20)(22,24)(25,27,31,26,32,34,30,35)(28,36,39,29,37,38,33,40)(11,17)(14,21)(18,19)(22,23)(25,28,30,33,32,37,31,39)(26,29,27,36,35,40,34,38)(9,12,13,20)(10,15,16,24)(11,18,17,19)(14,22,21,23)(25,29)(26,33)(27,37)(28,34)(30,36)(31,38)(32,40)(35,39)(1,4,5,3)(2,6,7,8)(10,16)(14,21)(15,24)(22,23)(25,30,32,31)(26,34,35,27)(28,33,37,39)(29,38,40,36)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.