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