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