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