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