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