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