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