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