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