3SAT and directed graph
I think you are trying to build the 2-SAT implication graph for 3-SAT.
In 2-SAT, $(x_a \vee x_b)$ may indeed be considered as 2 implications, $\neg x_a \Rightarrow x_b$ and $\neg x_b \Rightarrow x_a$.
The problem is that $(x_a \vee x_b \vee x_c)$ is not equivalent to any of the 6 implications like $\neg x_b \Rightarrow x_a$, as $x_c$ is sufficient to satisfy the clause.
You may eventually have $(\neg x_a \wedge \neg x_b) \Rightarrow x_c$ or $\neg x_a \Rightarrow (x_b \vee x_c)$, but neither let you build such implication graph.