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