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