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