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