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