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