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