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