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