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