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