This graph is the unique rank-3 $\mathrm{SRG}(256,135,70,72)$. The first subconstituent of this graph is the $\mathrm{O}_8^+(2)$ graph.
| Number of vertices: | $256$ |
| Diameter: | $2$ |
| Intersection array: | $\{135,64;1,72\}$ |
| Spectrum: | $135^1 7^{135} (-9)^{120}$ |
| Automorphism group: | $2^8:\mathrm{SO}^+(8,2)$ |
| Distance-transitive: | Yes |
| Primitive |