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