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