A splits graph is interpreted in terms of splits, or bipartitions, which divide the graph into two non-overlapping parts. If one wishes to refer to particular splits in a graph then one needs a way of highlighting those splits.
This can be done in a number of ways, some of them derived from conventions originating for the presentation of rooted phylogenetic trees. These include highlighting the taxa in one of the partitions, which is analogous to highlighting a clade in a rooted phylogenetic tree. Alternatively, we could colour the edges associated with each of the two partitions, as shown in this previous blog post (How to interpret splits graphs); however, this works only for a single split at a time.
Alternatively, it is also possible to label the edges of the splits themselves, as shown in this previous blog post (Representing evolutionary scenarios using splits graphs). Dabert et al. (Dabert M, Witalinski W, Kazmierski A, Olszanowski Z, Dabert J (2010) Molecular phylogeny of acariform mites (Acari, Arachnida): strong conflict between phylogenetic signal and long-branch attraction artifacts. Molecular Phylogenetics and Evolution 56: 222-241) present another possibility, which is to colour only the edges that separate to two partitions of each split, as shown in the figure.