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