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