There is a similar question with an answer that should also help you: see https://q2a.cs.uni-kl.de/3413/fdd-to-zdd-09-2022-1d

But it is not difficult: ¬b⊕a&b&c is almost in DNF:

¬b⨁a&b&c
= b&(¬1⨁a&1&c) | ¬b&(¬0⨁a&0&c)
= b&(a&c) | ¬b&(1⨁0)
= a&b&c | ¬b

For the set representation of the ZDD, Davio composition is useless (it is used for FDDs). Instead, you need the full DNF where all minterms are listed. In the above DNF, we just have one minterm a&b&c and a cube ¬b that is to be expanded to four minterms:

a&b&c | ¬b
= a&b&c | a&¬b | ¬a&¬b
= a&b&c | a&¬b&¬c | ¬a&¬b&¬c | a&¬b&c | ¬a&¬b&c

The latter gives us the set representation of the minterms:

{{a,b,c},{a},{},{a,c},{c}}

And now, we can draw the ZDD!