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