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