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