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)(15,20)(16,17)(18,19)(21,22,26,24)(23,28,25,27)(6,7)(8,12)(14,19)(17,20)(21,23)(22,27)(24,28)(25,26) involution — undirected(5,6,9,7)(8,10,12,11)(13,15,18,16)(14,20,19,17)(21,22,26,24)(23,28,25,27)(1,2,3,4)(5,7,9,6)(8,10,12,11)(13,16,18,15)(14,20,19,17)(21,24,26,22)(23,28,25,27)(5,8,9,12)(6,10,7,11)(13,17,18,20)(14,16,19,15)(21,25,26,23)(22,27,24,28)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.