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