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