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