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)(25,26,31,35)(27,32,33,38)(28,37,39,36)(29,34,30,40)(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)(28,34)(29,36)(30,37)(31,33)(35,38)(39,40)(9,12,14,11,13,21,15,20)(10,17,19,22,18,16,23,24)(25,28,29,38,31,39,30,32)(26,33,40,36,35,27,34,37)(1,4,5,3)(2,7,8,6)(10,18)(16,17)(19,23)(22,24)(25,29,31,30)(26,34,35,40)(27,36,33,37)(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.