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