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)(26,31)(27,35)(33,34)(36,37)(1,2,5,6)(3,7,4,8)(9,11,15,13)(10,16,14,18)(12,20,22,19)(17,24,21,23)(25,26,30,31)(27,32,35,38)(28,33,29,34)(36,39,37,40)(9,11,15,13)(10,16,14,18)(12,19,22,20)(17,23,21,24)(25,26)(27,32)(28,33)(29,34)(30,31)(35,38)(36,39)(37,40)(1,3,5,4)(2,7,6,8)(9,12,15,22)(10,17,14,21)(11,19,13,20)(16,23,18,24)(25,27,30,35)(26,32,31,38)(28,36,29,37)(33,39,34,40)(9,13,15,11)(10,16,14,18)(12,20,22,19)(17,23,21,24)(25,28,30,29)(26,33,31,34)(27,36,35,37)(32,39,38,40)(1,4,5,3)(2,8,6,7)(9,14,15,10)(11,18,13,16)(12,21,22,17)(19,24,20,23)(25,29,30,28)(26,34,31,33)(27,37,35,36)(32,40,38,39)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.