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