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