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