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