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