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