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