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