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