The three Chang graphs can be obtained by Seidel switching from T(8) (the line graph of K8). Namely, switch w.r.t. a set of edges that induces the following subgraph of K8: (a) 4 pairwise disjoint edges, (b) C3 + C5, (c) an 8-cycle C8.
|name||group size||max cliques||max cocliques|
 L.C. Chang, The uniqueness and nonuniqueness of triangular association schemes, Sci. Record 3 (1959) 604-613.
 L.C. Chang, Association schemes of partially balanced block designs with parameters v = 28, n1 = 12, n2 = 15 and p112 = 4, Sci. Record 4 (1960) 12-18.