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