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