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