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