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