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