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