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)(11,16)(12,17)(13,18)(14,15)(19,23)(20,21)(22,24)(25,26,31,33)(27,30,38,32)(28,29,35,34)(36,37,40,39)(2,5)(3,8)(9,11)(10,16)(12,19)(13,15)(14,18)(17,23)(20,24)(21,22)(25,27,31,38)(26,32,33,30)(28,36,35,40)(29,39,34,37)(1,3,6,8)(2,7,5,4)(10,14)(11,13)(17,20)(19,22)(26,33)(29,34)(30,32)(37,39)(1,4)(2,3)(5,8)(6,7)(9,12,15,21)(10,17,14,20)(11,19,13,22)(16,23,18,24)(25,28)(26,34)(27,36)(29,33)(30,39)(31,35)(32,37)(38,40)(1,5,6,2)(3,4,8,7)(9,13,15,11)(10,18,14,16)(12,19,21,22)(17,23,20,24)(25,29,31,34)(26,35,33,28)(27,37,38,39)(30,40,32,36)(1,4)(2,3)(5,8)(6,7)(9,14,15,10)(11,18,13,16)(12,20,21,17)(19,24,22,23)(25,30)(26,27)(28,39)(29,40)(31,32)(33,38)(34,36)(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.