Let $S_n$ be the symmetric group. let $H=S_{d_1}\times\cdots \times S_{d_k}$ such that $d_1+\cdots + d_k=n$.
What does the following statement means:
every two embeddings of $H$ in $S_n$ are conjugate.
In my opinion this means that changing the order of $d_i$ gives conjugate subgroups. For example $S_{d_1}\times S_{d_2}\times S_{d_3}$ is conjugate to $S_{d_2}\times S_{d_1}\times S_{d_3}$ and to $S_{d_3}\times S_{d_1}\times S_{d_2}$ and so on ...