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