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