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