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