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