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