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