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