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