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