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