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