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