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