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