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