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