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)(11,12)(13,15)(14,16)(17,18)(19,23)(20,22)(21,24)(25,26,30,29)(27,33,34,31)(28,36,37,32)(35,38,40,39)(1,2,5,3)(4,6,8,7)(17,19,22,21)(18,23,20,24)(26,29)(27,34)(32,36)(35,40)(2,3)(6,7)(9,11,14,13)(10,15,16,12)(17,19,22,21)(18,24,20,23)(25,27,30,34)(26,31,29,33)(28,35,37,40)(32,38,36,39)(1,3,5,2)(4,7,8,6)(9,12,14,15)(10,11,16,13)(17,20,22,18)(19,24,21,23)(25,28,30,37)(26,32,29,36)(27,35,34,40)(31,38,33,39)(1,4,5,8)(2,6,3,7)(9,13,14,11)(10,15,16,12)(17,21,22,19)(18,24,20,23)(25,29,30,26)(27,33,34,31)(28,36,37,32)(35,39,40,38)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.