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