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