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