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