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