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