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