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