Factsheet
Venn diagram
Mathematical Logic and venn diagrams - Mathematics Stack Exchange
Should "or" include the overlap, in a Decision Making Venn?
Two questions about venn diagrams and logical opposites
How do I represent “not A” in a diagram?
What is a symmetric difference (A Δ B)?
What is the difference between ∪ and ∩?
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How does this make sense because the intersection of an and b is part of b but it’s meant to be the union of an and b PRIME (everything not in b). The intersection is part of b tho…
A Venn diagram with three sets $A,B,C$ divides the universe into 8 distinct regions, as you can see in the picture below.

For example, the $A$ circle contains 4 regions: the upper region with an arrow pointing to it represents $A=true, B=false,\text{ and }C=false$, since that region is contained in $A$ but not in $B\text{ or }C$ For your function, the truth table already identifies the truth values of the points in each of the 8 regions. For each of these, place a marker in those regions where your truth table says the function evaluates to $true$, as I did in the other region pointed to by an arrow. Your function is $true$ in four cases; I've put a dot in each. (Your conventions for marking regions might differ from mine: you might want to shade them rather than placing a dot.)
A venn diagram is not usefull in this case because a?b:c is a short notation for if-the-else in algorithm programming and the truth value only depend of a, regardless if b or c are true or not because b and c represent operations and no conditionals, if a is true then the algorithm choose b and if a is false the algorithm choose c.