One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,3,4)(6,9)(7,11)(1,2)(3,4)(6,9)(10,12)(13,14)(15,23)(16,20)(17,21)(18,22)(19,25)(24,28)(26,27) involution — undirected(5,6)(7,10)(8,9)(11,12)(13,15,18,25)(14,19,22,23)(16,17,24,27)(20,26,28,21)(5,7,8,11)(6,10,9,12)(13,16,18,24)(14,20,22,28)(15,17,25,27)(19,26,23,21)(13,17)(14,21)(15,24)(16,25)(18,27)(19,20)(22,26)(23,28) involution — undirected(13,14)(15,19)(16,20)(17,26)(18,22)(21,27)(23,25)(24,28) involution — undirectedA 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.