As multicore systems continue to scale, cache coherence has emerged as a critical determinant of system performance, with coherence behavior and task execution closely intertwined, reshaping inter-task dependencies. Task graph modeling provides a structured way to capture such dependencies and serves as the foundation for many system-level design strategies. However, these strategies typically rely on predefined task graphs, while many real-world applications lack explicit graphs and exhibit dynamic, data-dependent behavior, limiting the effectiveness of static approaches. To address this, several task graph modeling methods for realistic workloads have been developed. Yet, they either rely on implicit techniques that use application-specific features without producing explicit graphs, or they generate graphs tailored to fixed scheduling models, which limits generality. More importantly, they often overlook coherence interactions, creating a gap between design assumptions and actual runtime behavior. To overcome these limitations, we propose CoTAM, a Coherence-Aware Task Graph Modeling framework for realistic workloads that constructs a unified task graph reflecting runtime behavior. CoTAM analyzes the impact of coherence by decoupling its effects from overall execution, quantifies its influence through a learned weighting scheme, and infers inter-task dependencies for coherence-aware graph generation. Extensive experiments show that CoTAM outperforms implicit methods, bridging the gap between dynamic workload behavior and existing designs while demonstrating the importance of incorporating cache coherence into task graph modeling for accurate and generalizable system-level analysis.