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