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