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