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