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