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