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