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