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