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