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)(11,19,23,31)(12,16)(13,17)(14,18)(15,22,20,26)(21,33,36,39)(24,29)(25,30)(27,32)(28,35,34,37)(38,40)(1,3,4,7)(2,5,6,8)(9,11,13,26,14,23,27,22)(10,15,17,31,18,20,32,19)(12,21,24,37,25,36,38,35)(16,28,29,39,30,34,40,33)(9,10)(11,20,23,15)(12,16)(13,17)(14,18)(19,22,31,26)(21,34,36,28)(24,29)(25,30)(27,32)(33,35,39,37)(38,40)(2,6)(5,8)(9,12,13,24,14,25,27,38)(10,16,17,29,18,30,32,40)(11,21,26,37,23,36,22,35)(15,28,31,39,20,34,19,33)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.