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