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