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