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