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