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