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