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