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