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