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