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