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