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