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