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