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