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