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