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