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