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