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