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