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