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