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