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