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