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