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