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