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