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