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