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