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