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