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