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