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