How to draw a clearly arranged DFA of a language with modulo rules? I know how to draw a DFA, but I have problems with this specific one: 

${L = \{ w \in \{a,b,c\}^* \mid \ |w|_a \equiv |w|_b - 2|w|_c \mod \ 5 \} }$

This language is regular and there has to exist a DFA (It would be great if someone could leave a comment WHY a language like this one is regular). Finally, I got a solution, but I'm not really satisfied with my solution. How can I present the DFA in a more clearly way? (is it possible to draw a "Planar graph" of it?)
Here is the minimal DFA. It keeps track of $|w|_a-|w|_b+2|w|_c\bmod 5$.