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