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