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